Biology

Photosynthesis in Plants

1,508 Questions

Photosynthesis is the biological process by which plants convert light energy into chemical energy. This page contains practice questions covering essential topics like chlorophyll, light reactions, and the pathways specific to plants. This material is crucial for medical entrance exams and academic assessments.

Chlorophyll and pigmentsLight reactionsCalvin cycleCAM plantsElectron transportPhotosynthesis factors

Photosynthesis in Plants Questions

Multiple choice

When are the carbohydrates formed in the plants?

  1. During respiration

  2. During night

  3. During water absorption by roots

  4. During photosynthesis

  5. During transpiration
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The carbohydrates are formed in the plants during photosynthesis.

Multiple choice

Which of the following statements are incorrect about photo system I?

A. PS I lies in outer surface of thylakoids. B. Reaction centre of PS I is P680. C. It participates in both cyclic as well as non-cyclic phosphorylation. D. Molecular oxygen is evolved as a result of photolysis of water.

  1. A and B

  2. A and C

  3. A and D

  4. B and C

  5. B and D
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because reaction centre of PS I is P700 and molecular oxygen is not evolved in PS I. It is evolved as a result of photolysis of water in PS II.

Multiple choice

Which of the following statements are incorrect about photosynthesis?

  1. Best photosynthesis takes place in green light.
  2. Quantum yield of photosynthesis is 0.125.
  3. Energy conversion efficiency of photosynthesis is 66%.
  4. 90% of the total photosynthesis in the world is carried out by marine algae.

  1. 1 and 2

  2. 1 and 3

  3. 1 and 4

  4. 2 and 3

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because energy conversion efficiency of photosynthesis is 33% and best photosynthesis takes place in red light, next best in blue light and nil in green light.

Multiple choice

Which of the following statements are correct about non-cyclic phosphorylation?

  1. It is an oxygenic process.
  2. Only one light trapping system (PS I) is involved.
  3. No NADPH is synthesised.
  4. NADP acts as last electron acceptor.

  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 1 and 4

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is wrong because non-cylic phosphorylation is an oxygenic process, i.e. oxygen is given off during the process and NADP acts as last electron acceptor in non-cyclic phosphorylation.

Multiple choice

Match the following:

 
Scientists Their contribution
P. Emerson and Arnold 1. O2 comes from H2O in photosynthesis
Q. Ruben and Kamen 2. Chloroplasts as the site of photosynthesis
R. Arnon 3. Mechanism of phosphorylation in chloroplast
S. Engelmann 4. Existence of light and dark reaction in photosynthesis

  1. P - 2, Q - 1, R - 3, S - 4

  2. P - 2, Q - 3, R - 4, S - 1

  3. P - 3, Q - 1, R - 4, S - 2

  4. P - 3, Q - 4, R - 2, S - 1

  5. P - 4, Q - 2, R - 3, S - 1
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because all are correctly matched. In 1932, Emerson and Arnold proved the existence of light and dark reaction in photosynthesis. In 1939, Samuel Ruben and Martin Kamen used radioactive isotopes to determine that the oxygen liberated in photosynthesis came from the water. In 1954, Arnon discovered the mechanism of phosphorylation in chloroplasts. In 1881, Theodore Engelmann identified chloroplasts as the site of photosynthesis.

Multiple choice

Which of the following herbicides do not interfere in light reaction of photosynthesis?

P. 2,4-D Q. Diuron R. Glyphosate S. Atrazine

  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. Q and S
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because 2,4-D and gyphosate do not act as interfering in light reaction of photosynthesis. 2,4-D is a synthetic auxin herbicide, have several points of action on the cell membrane and are effective in the control of dicot plants. Glyphosate is a systemic enolpyruvylshikimate 3-phosphate synthase (EPSPS) enzyme inhibitor herbicide.

Multiple choice

The raw materials for dark reaction are

  1. CO2, NADPH2 and ATP

  2. Water, ADP and H3PO4

  3. NADP, H3PO4 and ADP

  4. NADPH2, ATP and O2

  5. Hexose sugar
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CO2, NADPH2 and ATP act as the raw materials for dark reaction.

Multiple choice

Match the following:

 
Column – I (Scientists) Column – II (Their contribution)
P. Hill and Bendal 1. Z-scheme of light reaction
Q. Peter Mitchell 2. Chemiosmotic hypothesis of ATP synthesis in light reaction
R. Hatch and Slack 3. C3 pathway for CO2 fixation
S. Melvin Calvin 4. C4 pathway for CO2 fixation

  1. P - 1, Q - 2, R - 3, S - 4

  2. P - 2, Q - 1, R - 4, S - 3

  3. P - 3, Q - 2, R - 1, S - 4

  4. P - 4, Q - 3, R - 2, S - 1

  5. P - 1, Q - 2, R - 4, S - 3
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Correct answer. In 1960, Hill and Bendal suggested Z-scheme of light reaction. In 1961, Peter Mitchell proposed chemiosmotic hypothesis of ATP synthesis in light reaction. In 1966, Hatch and Slack reported the C4 pathway for CO2 fixation in certain tropical plants. In 1954, Melvin Calvin traced the path of carbon in photosynthesis and gave the C3 cycle (now known as Calvin cycle).

Multiple choice

Which of the following statements are correct about dark reaction?

P. Source of energy for dark reaction is ATP synthesised in light reaction. Q. Raw materials of dark reaction are water, ADP and H3PO4. R. Oxygen is a by-product of dark reaction and is released in the atmosphere. S. Dark reaction occurs in stroma of chloroplast.

  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. R and S
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because source of energy for light reaction is sunlight whereas source of energy for dark reaction is ATP synthesised in light reaction. The site for action of dark reaction is stroma of chloroplast.

Multiple choice

Which of the following statements is/are not correct about chlorophyll?

  1. The metal constituent of chlorophyll is Fe.
  2. Chlorophyll is found associated with thylakoid membranes.
  3. Long-chain alcohol esterified to plant chlorophyll molecules is farnesol.

  1. Only 1

  2. Only 2

  3. Only 3

  4. 1 and 2

  5. 1 and 3
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because the metal constituent of chlorophyll is Mg and long-chain alcohol esterified to plant chlorophyll molecules is phytol.

Multiple choice

Plastids are important for green plants because

  1. they trap solar energy

  2. they store proteins

  3. they synthesise energy

  4. they regulate cell function
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plastids are responsible for trapping solar energy so as to synthesise carbohydrates in the photosynthetic plants.